JP5059792B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus for performing plasma processing on a target object such as a glass substrate for manufacturing a flat panel display (FPD) or a semiconductor wafer for manufacturing a semiconductor integrated circuit (IC).

  In an FPD or IC manufacturing process, a plasma processing apparatus that performs processing such as etching on a target object such as a glass substrate or a semiconductor wafer is used. As a plasma processing apparatus that performs processing such as etching, for example, a plasma dry etching apparatus is well known.

  An apparatus controller for controlling process gas and high-frequency output is connected to the plasma dry etching apparatus. The apparatus controller controls the flow rate of the process gas, the high-frequency output, the processing time, the processing pressure, and the like according to predetermined processing conditions called process recipes. Thereby, a predetermined process such as etching of the object to be processed by the plasma processing apparatus is executed.

  When a process abnormality or the like occurs while executing a predetermined process, for example, as described in Patent Document 1, the process for the object to be processed is interrupted. After the interruption, the operator performs necessary operations such as correction of the recipe, and then re-executes the processing for the object to be processed.

JP 2007-234809 A

  As described in Patent Document 1, when a predetermined process is executed, if a process abnormality occurs, the process is interrupted. For this reason, there is a situation that the productivity of the product is lowered.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a plasma processing apparatus capable of suppressing a decrease in productivity even when a process abnormality or the like occurs.

  In order to solve the above-described problems, a plasma processing apparatus according to one aspect of the present invention is a plasma processing apparatus including a processing chamber that performs plasma processing on a target object according to processing conditions. A storage unit that stores a plurality of different reprocessing conditions, a monitoring function that monitors whether or not an abnormality has occurred during the plasma processing, and a determination function that determines the type of abnormality that has occurred. In the case of occurrence, a control system is provided that selects one reprocessing condition from the plurality of reprocessing conditions according to the determined type of abnormality and performs reprocessing on the object to be processed.

  According to the present invention, it is possible to provide a plasma processing apparatus capable of suppressing a decrease in productivity even when a process abnormality or the like occurs.

Sectional drawing which shows roughly an example of the plasma processing apparatus which concerns on one Embodiment of this invention 1 is a block diagram schematically showing a control system for controlling the plasma processing apparatus 1 shown in FIG. 1 is a flowchart showing an example of a substrate processing method executed by an apparatus controller included in a plasma processing apparatus according to an embodiment. Diagram showing an example of processing condition change 1 is a flowchart showing an example of a sequence of substrate processing performed by a plasma processing apparatus according to an embodiment. 6A is a diagram showing process information for each elapsed processing time of a glass substrate G that has been processed normally, and FIG. 6B is a diagram showing process information for each elapsed processing time of the glass substrate G in which an abnormality has occurred. Diagram showing the relationship between discharge level and time

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view schematically showing an example of a plasma processing apparatus according to an embodiment of the present invention.

  A plasma processing apparatus 1 shown in FIG. 1 is an example of an apparatus that performs a predetermined process on a glass substrate G for FPD production. In this example, the plasma processing apparatus 1 is configured as a capacitively coupled plasma dry etching apparatus. Examples of the FPD include a liquid crystal display (LCD), an electroluminescence (EL) display, a plasma display panel (PDP), and the like.

  The plasma processing apparatus 1 includes, for example, a processing chamber (plasma processing chamber) 2 formed into a rectangular tube shape made of aluminum whose surface is anodized (anodized). A placing table 3 for placing a glass substrate G, which is an object to be processed, is disposed at the bottom of the processing chamber 2.

  The mounting table 3 is supported on the bottom of the processing chamber 2 via an insulating member 4. The mounting table 3 is composed of a conductive substrate 5 having a convex portion 5a. The surface of the conductive substrate 5 is covered with an insulating coating 8, for example, alumina spraying or alumite. The periphery of the convex portion 5 a is surrounded by a frame-shaped focus ring 6. In this example, the feeder 12 is connected to the conductive substrate 5. The feeder line 12 is connected to a high frequency power source 14 via a matching unit 13. The high frequency power supply 14 outputs high frequency power of 13.56 MHz, for example. The high-frequency power is supplied to the conductive base material 5 constituting the mounting table 3 through the matching unit 13 and the feeder line 12. Thereby, the mounting table 3 functions as a lower electrode.

  A shower head 20 is arranged above the mounting table 3 so as to face the mounting table 3. The shower head 20 is supported by the upper part of the process chamber 2, for example. The shower head 20 has an internal space 21 inside and a plurality of discharge holes 22 for discharging a processing gas on the surface facing the mounting table 3. Thereby, the shower head 20 functions as a process gas discharge part. In this example, the shower head 20 is grounded and functions as an upper electrode, and constitutes a pair of parallel plate electrodes together with the mounting table 3 functioning as a lower electrode.

A gas inlet 24 is provided on the upper surface of the shower head 20. A processing gas supply pipe 25 is connected to the gas inlet 24. The processing gas supply pipe 25 is connected to a processing gas supply source 28 via an open / close valve 26 and a mass flow controller (MFC) 27. The processing gas supply source 28 supplies a processing gas used for plasma processing, for example, plasma dry etching, into the processing chamber 2 via the mass flow controller 27, the opening / closing valve 26, the processing gas supply pipe 25, and the shower head 20. To do. As the processing gas, a gas usually used in this field, such as a halogen-based gas, an O ₂ gas, or an Ar gas, can be used.

  An exhaust pipe 29 is formed at the bottom of the processing chamber 2. The exhaust pipe 29 is connected to the exhaust device 30. The exhaust device 30 includes a vacuum pump such as a turbo molecular pump (TMP). The exhaust device 30 exhausts the inside of the processing chamber 2 by adjusting the exhaust amount. Thereby, the pressure in the processing chamber 2 can be reduced to a predetermined reduced pressure atmosphere.

  A substrate loading / unloading port 31 is provided on the side wall of the processing chamber 2. The substrate loading / unloading port 31 can be opened and closed by a gate valve 32. With the gate valve 32 opened, the glass substrate G is loaded and unloaded by a transfer device (not shown).

  FIG. 2 is a block diagram schematically showing a control system for controlling the plasma processing apparatus 1 shown in FIG.

  As shown in FIG. 2, the device controller 50 includes a matching unit 13, a mass flow controller 27, an exhaust device 30, an end point detector 51 that detects an end point of etching based on plasma emission intensity in the processing chamber 2, and the high frequency power source 14. Are connected to a high frequency generator 52 for generating a high frequency output.

  The controller 50 has a storage unit that stores processing conditions (process recipes). The apparatus controller 50 controls the mass flow controller 27, and the flow rate of the processing gas according to the processing conditions (process recipes) stored in the storage unit. Adjust.

  Similarly, the device controller 50 controls the exhaust device 30, adjusts the exhaust amount according to the process recipe, and adjusts the pressure in the processing chamber 2.

  Furthermore, the device controller 50 controls the high frequency generator 52 and adjusts the output value of the high frequency power supplied to the mounting table 3 according to the process recipe.

  Further, the device controller 50 controls the temperature control device for the heat transfer medium flowing in the heat transfer medium flow path incorporated in the mounting table 3 and controls the temperature of the glass substrate G according to the process recipe. Adjust.

  Thus, the apparatus controller 50 controls the plasma processing apparatus 1 by controlling the mass flow controller 27, the exhaust apparatus 30, the high frequency generator 52, and the temperature control apparatus.

  The apparatus controller 50 has not only a function of controlling the plasma processing apparatus 1 but also a monitoring function of monitoring the processing status.

  Specifically, the apparatus controller 50 monitors the flow rate of the processing gas in the mass flow controller 27 and monitors the supply status of the processing gas.

  Similarly, the device controller 50 monitors the exhaust amount in the exhaust device 30 and monitors the pressure state in the processing chamber 2.

  Similarly, the device controller 50 monitors the output value of the high frequency generator 52 and monitors the output status of the high frequency output.

  Similarly, the device controller 50 monitors the temperature adjusting device, and monitors the temperature of the glass substrate G and the temperature state in the processing chamber 2.

  Similarly, the apparatus controller 50 monitors the plasma emission intensity detected by the end point detector 51 and monitors the plasma state in the processing chamber 2. Further, the apparatus controller 50 monitors the magnitude of the reflected wave of the high frequency power returning to the high frequency generator 52 (hereinafter simply referred to as the reflected wave), and monitors the state of the plasma in the processing chamber 2.

  Furthermore, the apparatus controller 50 selects a reprocessing condition stored in advance in the storage unit and sets a necessary value when an abnormality, for example, a process abnormality occurs when processing the glass substrate G. Then, the plasma processing apparatus 1 is controlled so that the glass substrate G is reprocessed. FIG. 3 shows an example of a substrate processing method executed by the apparatus controller 50.

  As shown in FIG. 3, the device controller 50 stores basic processing conditions. The basic processing condition includes a basic condition that is a processing condition (process recipe) and a specified value for determining whether or not a process abnormality has occurred. In the basic conditions, the flow rate of the processing gas, the type of the processing gas, the pressure in the processing chamber 2, the output value of the high frequency power, the processing time, and the like are set. The specified values are the plasma emission intensity and the output value of the high frequency power obtained from each unit (matching unit 13, mass flow controller 27, exhaust device 30, end point detector 51, high frequency generator 52, temperature control device (not shown)). , The reflected wave, the substrate or the temperature in the processing chamber 2.

  An example of the specified value is to set the plasma emission intensity, the output value of the high-frequency power, the reflected wave, and the temperature in the processing chamber 2 observed in the glass substrate G that has been processed normally as the specified value. When processing the glass substrate G, the apparatus controller 50 monitors the plasma emission intensity, the output value of the high frequency power, the reflected wave, the temperature in the substrate or the processing chamber 2, and at least one of these values is monitored. If a change that deviates from the specified value occurs, it is determined that an abnormality has occurred. The device controller 50 also has a determination function for determining the type of abnormality. The determination of the type of abnormality may be made, for example, based on which specified value has deviated from among the plasma emission intensity, the output value of the high frequency power, the reflected wave, and the temperature in the substrate or the processing chamber 2.

  For example, n determination results from determination-1 to determination-n are stored in the storage unit of the device controller 50, and a change deviating from a specified value matches which determination result among the n determinations. The type of abnormality is determined by searching for these.

  Furthermore, in this example, a plurality of reprocessing conditions corresponding to each of the n determination results are stored in the storage unit of the device controller 50. The reprocessing condition is at least one of the flow rate of the processing gas, the type of the processing gas, the pressure in the processing chamber 2 (the exhaust amount in the processing chamber 2), and the output value of the high-frequency power with respect to the processing condition (basic condition). Is different.

  For example, as shown in FIG. 4A, it is assumed that the reflected wave instantaneously rises when the processing time is 110 seconds. If the determination at this time is “determination-1”, “condition-1” is selected as the reprocessing condition. Further, as shown in FIG. 4B, it is assumed that the plasma emission suddenly decreases when the processing time is 140 sec. If the determination at this time is “determination-2”, “condition-2” is selected as the reprocessing condition.

  The apparatus controller 50 changes the basic conditions, for example, the flow rate of the processing gas, the pressure in the processing chamber 2, the output value of the high frequency power, and the processing time to the reprocessing conditions selected according to the determination result. Then, the device controller performs reprocessing on the glass substrate G according to the selected reprocessing conditions.

  As described above, according to the plasma processing apparatus according to the embodiment, the apparatus controller 50 automatically selects and executes an appropriate reprocessing condition according to the processing state of the glass substrate G and the state of the apparatus. . Thereby, it is possible to obtain a plasma processing apparatus capable of suppressing a decrease in productivity even when a process abnormality occurs.

  Next, an example of a specific substrate processing sequence will be described below.

  FIG. 5 is a flowchart illustrating an example of a substrate processing sequence performed by the plasma processing apparatus according to the embodiment.

  As shown in FIG. 5, it is assumed that some abnormality has occurred during execution of the process (step 1).

  In step 1, it is determined whether the abnormality that has occurred is a serious abnormality or a minor abnormality.

  Severe abnormalities include abnormalities in equipment such as failure to transport the glass substrate G, broken electrodes, broken high frequency power supply, etc., and are abnormalities in which processing cannot be continued (killer alarm). When a killer alarm is issued, the process is stopped.

  Minor abnormalities include an instantaneous increase in reflected waves, non-standard high-frequency output fluctuations, non-standard pressure fluctuations, non-standard process gas flow fluctuations, non-standard temperature fluctuations There is an abnormality (normal alarm) that is likely to be able to continue the processing, such as (in the processing chamber and / or glass substrate). When a normal alarm is generated, the process proceeds to an abnormality diagnosis step (step 2).

  In step 2, the type of abnormality is determined, and it is determined whether the process can be continued or not as a result of the determination.

  The type of abnormality is determined based on, for example, the timing at which the abnormality has occurred and the information of the unit that detected the abnormality. For example, the process information of the glass substrate G that has been processed normally most recently is recorded in the storage unit of the apparatus controller 50. For example, when the device controller 50 is processed using the B recipe for the A type, the emission intensity D of the plasma is reached after the elapse of C time, the emission intensity F is elapsed after the elapse of E time, and the process is completed in G time. As described above, the process information for each processing elapsed time is sampled. The process information sampled at each processing elapsed time includes, for example, the temperature of the processing chamber or the glass substrate G, the output value of the high frequency power, the intensity of plasma emission, and the reflected wave when the glass substrate G is processed normally. Information on how the size changes for each processing elapsed time is included. For example, the process information for each elapsed processing time is set as a predetermined value for determination, and the progress of the process and the possibility of reprocessing are determined.

  When it is determined that the process cannot be continued, the process is stopped (reprocessing is not possible).

  When it is determined that the process can be continued (reprocessing is possible), the process proceeds to a reprocessing condition setting step (step 3).

  In step 3, reprocessing conditions are set for the glass substrate G in which process abnormality is detected.

  The reprocessing condition is set by selecting an optimum reprocessing condition from a plurality of preprocessed reprocessing conditions according to the determined abnormality type. For example, when the instability of the plasma state causes an abnormality, such as when the reflected wave becomes excessive instantaneously, a reprocessing condition for reducing only the high-frequency output is selected.

  Further, the time during which the glass substrate G is normally processed before abnormality detection is calculated, and the necessary reprocessing time is set in consideration of the change in the high-frequency output. When the end point detection is not used, or when the end point cannot be detected, the process ends with the set reprocessing time.

  A specific example of setting reprocessing conditions will be described with reference to FIGS. 6A and 6B.

  FIG. 6A shows process information for each processing elapsed time of a glass substrate G processed normally under the basic condition of a high-frequency output of 10 kW, and shows a fluctuation waveform according to the processing time of plasma emission intensity and reflected wave. ing.

  As shown in FIG. 6A, the glass substrate G processed normally has a total processing time of 110 sec. The fluctuations in plasma emission intensity and reflected wave for each processing elapsed time are as follows.

Process elapsed time 60 sec: Plasma emission intensity decreases and reflected waves increase
Process elapsed time 80 sec: Plasma emission intensity decreases again
Process elapsed time 100 sec: lower limit of plasma emission intensity (just etching)
Processing elapsed time 110 sec: End of processing
FIG. 6B shows process information for each processing elapsed time of the glass substrate G in which an abnormality has occurred under the basic condition of a high frequency output of 10 kW. In the example shown in FIG. 6B, the reflected wave is instantaneously excessive when the processing elapsed time is 58 sec. Here, FIG. 6B shows process information until an abnormality occurs. In this example, the device controller 50 determines that the process can be continued, and sets the reprocessing conditions as follows.

  Since the type of abnormality is “the reflected wave becomes excessive instantaneously”, the device controller 50 reduces only the high-frequency output from the basic condition to 5 kW out of a plurality of reprocessing conditions stored in advance in the storage unit. Select the reprocessing condition to be executed.

  In addition, a reprocessing time is also set in case the end point cannot be detected. Regarding the reprocessing time, since the high-frequency output was reduced to 5 kW, a time obtained by subtracting the time (58 sec) during which the glass substrate G was normally processed before the abnormality was detected from the total processing time (110 sec) when the normal processing was performed. Is doubled and set to 104 sec.

  After setting the reprocessing conditions in this way, the process proceeds to step 4 to execute reprocessing (addition processing). Thereafter, as shown in step 5, when the end point of etching is detected, the process is terminated (end is possible). When the end point is not detected, as shown in step 6, a time corresponding to the set reprocessing time is set. The process is terminated by control (cannot be terminated).

  Although an example of a specific sequence has been described above, since the execution of the reprocessing condition is automatically performed by the apparatus controller 50, the time from the abnormality detection to the start of execution of the reprocessing condition is extremely short. Therefore, at the time of abnormality detection, the device controller 50 may control the high-frequency generator 52 to stop the high-frequency output once or not. Alternatively, as shown in FIG. 7, the high frequency generator 52 is controlled so as to reduce the high frequency output to the minimum output necessary for maintaining the plasma from the time of abnormality detection to the start of execution of the reprocessing condition, A weak discharge state in which processing such as etching does not proceed may be employed.

  By providing such an apparatus controller 50 as a control system, it is possible to obtain a plasma processing apparatus that can suppress a decrease in productivity even when a process abnormality occurs.

  As mentioned above, although this invention was demonstrated by one Embodiment, this invention is not limited to the said one Embodiment, A various deformation | transformation is possible. For example, the reprocessing condition may be a condition based on the value of the basic condition such as “reducing the high-frequency output value of the basic condition to 50%”. Under such conditions, the high frequency output can be reduced even if the basic conditions change.

  Further, the embodiment of the present invention is not the only one described above.

  For example, in the above-described embodiment, the present invention has been shown for the case where the present invention is applied to the plasma dry etching processing of a glass substrate for FPD production. However, the present invention is not limited to this, and other substrates such as a solar cell substrate or a semiconductor wafer are used. The present invention can also be applied to an apparatus that processes a processing body.

  Further, the plasma dry etching process is shown as the process, but the present invention is not limited to the plasma dry etching process, and can be applied to a film forming process such as CVD or PVD.

  In the above embodiment, the capacitively coupled plasma apparatus in which the high frequency power source 14 is connected to the mounting table 3 is shown. However, for example, the capacitively coupled type in which the high frequency power source 14 and a high frequency power source having a different frequency are connected to the mounting table 3. The present invention can be applied to a plasma apparatus, or an inductively coupled plasma apparatus or a plasma apparatus using microwaves.

  DESCRIPTION OF SYMBOLS 2 ... Processing chamber (processing chamber), 5 ... Base material (lower electrode), 5a ... Convex part, 5b ... Flange part, 6 ... Focus ring, 13 ... Matching device, 14 ... High frequency power supply, 27 ... Mass flow controller, 30 ... Exhaust device, 50 ... device controller, 51 ... end point detector, 42 ... high frequency generator.

Claims (6)

A plasma processing apparatus including a processing chamber for performing plasma processing on a target object according to processing conditions,
A control system comprising a storage unit that stores a plurality of reprocessing conditions different from the processing conditions, a monitoring function that monitors whether or not an abnormality has occurred during the plasma processing, and a determination function that determines the type of abnormality that has occurred Comprising
When an abnormality occurs during the plasma processing, the control system selects one reprocessing condition from the plurality of reprocessing conditions according to the determined type of abnormality, and applies to the object to be processed. A plasma processing apparatus, wherein reprocessing is performed.   When an abnormality occurs during the plasma processing, the control system determines whether the plasma processing can be continued, and selects one reprocessing condition when determining that the processing can be continued. The plasma processing apparatus according to claim 1, wherein reprocessing is performed on the object to be processed.   The storage unit stores in advance predetermined values relating to the temperature of the object to be processed or the processing chamber, the emission intensity of the plasma, and the magnitude of the reflected wave of the high frequency power for generating and maintaining the plasma, and the object to be processed during the plasma processing is stored. The control system determines that an abnormality has occurred when a temperature of a processing object, a light emission intensity of the plasma, and a magnitude of the reflected wave deviate from the specified values. The plasma processing apparatus according to claim 2.   The control system includes the temperature of the object to be processed or the processing chamber for each processing elapsed time in the object to be processed that has been normally processed, the value of the high-frequency output, the intensity of the plasma emission, and the magnitude of the reflected wave. The plasma processing apparatus according to claim 3, wherein the specified value is set for each processing elapsed time and stored in the storage unit. The control system controls a processing gas supply system that supplies a processing gas into the processing chamber, an exhaust system that exhausts the processing chamber, and a high-frequency power supply system that supplies high-frequency power for generating and maintaining plasma into the processing chamber. ,
The reprocessing condition is characterized in that at least one of a flow rate of the processing gas, a type of the processing gas, an exhaust amount in the processing chamber, and an output of the high-frequency power is different from the processing condition. The plasma processing apparatus according to any one of claims 1 to 4.   The control system determines the minimum output necessary for maintaining plasma from the time when it is determined that an abnormality has occurred until the object to be processed is reprocessed. The plasma processing apparatus according to any one of claims 1 to 5, wherein the plasma processing apparatus is configured as follows.

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